It's been recognized that automatic sprinkler systems, which respond to heat generated by a fire, can be important additions to building monitoring or fire alarm system. One of the advantages of the sprinkler systems is that they respond automatically to local heat and can be effective in suppressing fires even before any of the first responders such as fire or police arrive at the scene.
Known sprinkler systems and sprinkler heads are passive devices which respond to localized heat to melt a material, which could be a metal, which then permits the head to start spraying pressurized water from the associated distribution system. It's been recognized that this configuration has the disadvantage that the associated fire monitoring system does not receive any signals from the sprinkler heads which indicate which heads have gone active, into an alarm state, and which heads have not.
While a variety of flow sensors have been developed which can be installed in sprinkler standpipes to provide an indication of water flow, knowledge of which sprinkler head or heads have opened would require installing and powering flow sensors in pipes leading to nearly each head, which would be costly. However, it may be very important and useful to first responders to know which sprinklers have opened. In addition to limited information obtainable from flow sensors, they represent ongoing maintenance problems and expense. Further, known flow sensors are coupled to the alarm system by hard wiring.
Thus there continues to be a need for devices which cost effectively make it possible to identify specific, active, sprinkler heads. Further, it would be desirable to be able to incorporate such devices into known types of sprinkler heads, perhaps even be able to retrofit them, without requiring substantial and expensive changes to the structure of such heads.